ACTIVE TO PASSIVE TENSE CHANGES
When trying to use passive voice or even transform active sentence into passive, you should follow the following rules:    PASSIVE VOICE FOR ALL TENSES RULES   The  places  of subject and object in sentence are inter-changed in  passive voice .  3rd form of verb (past participle) will be used only (as main verb) in passive voice.  Auxiliary verbs for each tense are given below in the table.      Present Simple  Tense (passive Voice)  Auxiliary verb in passive voice: am/is/are    Active voice :  He  sings  a song.  He does not sing a song.Does he sing a song?   Passive voice:  A song  is   sung  by him.  A song  is  not sung by him.  Is  a  song sung  by him?       Present Continuous Tense (passive Voice) Auxiliary verb in passive voice: am being/is being/are being    Active voice:  I am writing a  letter  I am not writing a letter.  Am I writing a letter?   Passive voice:  A let...